A focal plane array (FPA) is a matrix of detector cells. FPAs are frequently connected to or built on a semiconductor chip. FPA detector cells are composed of materials that are responsive to particular frequencies of electromagnetic radiation (EMR). The particular frequencies the detector cells are responsive to depends on the application. The response of all the detector cells in the array can be combined to form a composite image. One of the most common imaging application is digital photography, i.e. generating an image from detector cells that are responsive to frequencies in the visible light range. However, there is a growing market for devices that create images from detector cells that are responsive to a variety of electromagnetic frequencies including those not in the visible light spectrum.
Microbolometers have FPAs consisting of detector cells made from materials that produce a change in electrical resistivity in accordance with a temperature change i.e. a change in infrared radiation. Commercially available microbolometers have FPAs with a resolution of 320×240 and a response speed of 30 fps. Micrcobolometers are an uncooled type of bolometer as opposed to a cooled type which typically requires cryogenic cooling to minimize noise. Cooled sensors offer greater sensitivity, but are more expensive because of the cost required to cool them. Furthermore, mircobolometers are limited by their response speed. Thus, it is desirable to produce a microbolometer type device with increased sensitivity and a better response speed, but without the added costs of temperature controls.
The more specific aspects of the various other focal point arrays and the various other devices which employ them are known to the artisan and for brevity will not be repeated herein.
U.S. patent application Ser. No. 11/400,280, noted above describes various arrangements of ultra-small resonant structures that can be used to angularly modulate a beam of charged particles directed past them, when exposed to incoming or received EMR. The ultra-small structure(s) may comprise, for instance, any number of nano-sized resonant structures constructed and adapted to angularly modulate a beam of charged particles in responses to observed electromagnetic waves such that EMR can be detected e.g., as described above and/or in U.S. patent applications Ser. Nos. 11/243,476; 11/400,280 (each described in greater detail above).
It is desirable to use one or more ultra-small resonant structures or arrays thereof, to create a FPA for use in imaging applications, in particular mircobolometery.